Electroresponsive control



May 5, 1959 R. s. MATTHEWS 2,835,605

ELECTRORESPONSIVE CONTROL Filed D80. 9, 1955 1:19 T0 CON TR 0L T0 C04 7 R01.

CIRCUIT a z INVENTOR.

[Russell E. New: ears :3? a are United States Patent ELECTRORESPONSIVE CONTROL Russell B. Matthews, Wauwatosa, Wis., assignor to Base Inc., Milwaukee, Wis., a corporation of Wisconsin Application December 9, 1955, Serial No. 552,218 1?- Claims. (Cl. 317--133.5)

This invention relates to improvements in electro-responsive control apparatus and more particularly to control apparatus performing a safety function.

Certain electroresponsive safety devices, for example those having a control member actuated to a safety position by response of said devices to a predetermined unsafe condition, cannot perform their safety function and are themselves unsafe if a break should occur in their energizing circuits. Such a break could occur, for example, in extended leads connecting said device to a source of electrical energy, for example a thermoelectric generator, and it could also occur within windings of the device itself.

It is a general object of the present invention to provide an improved electroresponsive control apparatus having a control member movable from an operating position to a safety position on occurrence of a predetermined unsafe condition, said apparatus also being responsive to actuate said control member to its safety position on occurrence of a break in the electrical circuit thereof.

Another object of the invention is to provide an improved control apparatus of the aforementioned character having a thermoelectric generator for sensing the temperature of a medium, said generator having extended leads and being operable in response to a predetermined temperature in said medim'n to effect actuation of the control member of said apparatus to its safety position, there being a control circuit under the control of said control member, which circuit includes a portion substantially coextensive with said generator leads, Wherefore a break in either of said leads effects actuation of the control member to its safety position, and a break in the aforementioned control circuit portion prevents the flow of energizing current through said control circuit irrespective of the position of the control member.

Another object of the invention is to provide an improved control apparatus of the class described having an electromagnetic operator provided with a flux generating winding having portions which normally generate substantially equal magnitudes of opposing flux having no substantial actuating effect on the control member, occurrence of a break in the circuit to either of said winding portions terminating the generation of flux therein and the opposition afforded thereby, whereupon the flux generated in the other winding portion is operable to actuate the control member to its safety position.

Still another object of the invention is to provide an improved control apparatus of the aforementioned character wherein the thermoelectric generator is connected to the flux generating winding in such a manner that the flux generated by the thermoelectric current flow in one of the winding portions aids that generated by said thermoelectric current flow in the other winding portion, the thermoelectric current flow through said winding being superimposed upon the current flow through said winding portions generating the aforementioned opposing fluxes.

Still another object of the invention is to provide an improved electroresponsive control apparatus of the character aforedescribed wherein alternating current is utilized for generation of the opposing fluxes and for energization of the control circuit.

Other and further objects of the invention will become apparent as the description proceeds, reference being had to the accompanying drawing illustrating two forms of the invention, wherein:

Figure 1 is a semi-diagrammatic view of one form of the invention; and

Figure 2 is a View similar to Figure 1 illustrating another form of the invention.

Referring more particularly to Figure l of the drawing, the form of the invention selected for illustration therein comprises a control device 5 which may take the form of a relay for controlling the flow of energizing current from a source, for example an alternating current source 6 through a control circuit (not shown). The relay 5 comprises an electromagnetic operator 7 having a magnetically permeable core 8 which may be generally U-shaped in conformation and is provided with an energizing winding 9.

A magnetically permeable armature cooperates with the pole faces of the core 8 and is preferably suitably biased toward the retracted position shown, said armature being movable to an attracted position with respect to said pole faces. The armature 10 is connected, as by a stem 11 to a contact bridging member 12 cooperable with a pair of contacts 13 and 14 and disposed in circuit-making relation with respect thereto as shown when the armature 10 is in its retracted position, said contact bridging member being movable on attractive movement of the armature 10 to a circuit-interrupting position with respect to the contacts 13 and 14.

The relay 5 is provided with a pair of input terminals 17 and 18 for connection with the source 6, and is also provided with output terminals 19 and 20 for connection with the control circuit. The contacts 13 and 14 are interposed in a conductor 15 which connects the input terminal 17 in circuit with the output terminal 20 as shown, and a conductor 21 connects the input terminal 18 in circuit with the output terminal 19 as shown.

Means is provided for energizing the electromagnet winding 9, for example on occurrence of an unsafe temperature condition in a given medium, said means comprising a thermoelectric generator preferably in the form of a center tapped thermocouple 22 having a pair of dissimilar thermoelements 33 and 34 joined at a hot junction 23 subject to the temperature of the given medium, said thermoelements also having cold junctions 24 and 25. The thermocouple 22 may be located remote from the electromagnetic operator 7 and is connected in circuit with the winding 9 by means of elongated lead conductors 26 and 27. Occurrence of a predetermined unsafe temperature within the given medium produces a predetermined differential in temperature between the hot junction 23 and the cold junctions 24 and 25, whereupon the thermocouple generates a thermoelectric current Which flows through the electromagnet winding 9 from one end thereof to the other to cause generation of flux of sufiic-ient magnitude to link the armature 10 and actuate the latter from the retracted position shown to an attracted position with respect to the pole faces of the core 8. This armature move ment efiects corresponding movement of the contact bridging member 12 to circuit-interrupting position and prevents any further current flow from the source 6 to the control circuit as long as the unsafe condition prevails.

Means is also provided for efiecting attractive movement of the armature 10 and circuit-interrupting movement of the contact bridging member 12 on occurrence of a break anywhere in the circuit comprising the thermocouple 22, leads 26 and 27 and the winding 9, said means comprising a conductor 29 which connects the center tap 28 of the thermocouple 22 in circuit with the conductor 15, and a conductor 31 which connects a center tap 30 on the winding 9 in circuit with the conductor 21 as shown. The conductor 31 may have a dropping resistor 32 interposed therein for limiting the magnitude of alternating current which can flow through the winding 9.

The center tap 3t} divides the energizing winding into substantially equal portions 9a and 9b which respectively form portions of a pair of parallel paths through which th alternating current can flow between the conductors 31 and 29. One of the aforementioned parallel paths comprises the winding portion 9a, lead conductor 27 and thermoelement 34, and the other parallel path comprises the winding portion 91), lead conductor 26 and thermoelement 33. The flow of alternating current through the aforementioned parallel paths causes the winding portions 9a and 9b to generate opposing alternating current fluxes of substantially equal magnitude, and said opposing fluxes have substantially no actuating effect upon the armature 10.

During normal operation of the form of the improved control apparatus shown in Figure l, the parts are disposed as shown, and alternating current flows from the source 6 through conductors and 21 and the control circuit, and alternating current also flows through the aforementioned parallel paths between the conductors 31 and 29 to generate the aforementioned opposing fluxes. On occurrence of a predetermined unsafe temperature in the medium sensed by the thermocouple 22, a temperature differential is produced between the hot junction 23 and the cold junctions 24 and sufficient to generate a thermoelectric current which is superimposed on the alternating current in the winding 9 and flows through said winding from one end thereof to the other. The flux generated by the thermoelectric current flowing through the winding 9 actuates the armature 10 to attracted position and effects movement of the contact bridging member 12 from circuit-making to circuit-interrupting position.

If, during the normal operation of the improved control apparatus, a break should occur in either of the aforementioned parallel paths, for example in either of the winding portions 951 or 9b, lead conductors 25 and 27, or thermal elements 33 and 34, flow of alternating current through the path in which the break occurred is terminated, as is generation of alternating current flux in the portion of the winding 9 in said parallel path. Termination of this flux generation, of course, terminates the opposition of said flux to that generated in the winding portion in the other parallel path, whereupon the flux generated in said other winding portion is operable .to

actuate the armature 19 from retracted to attracted position and the contact bridging member 12 from circuitmaking to circuit-interrupting position. As aforementioned, whenever the contact bridging member 12 is moved to circuit-interrupting position, alternating current flow between the source 6 and the control circuit is prevented.

Figure 2 illustrates another form of control device constructed in accordance with the invention. In Figure 2, the elements indicated by primed reference characters may be identical with those indicated in Figure l by the same reference characters unprimed.

In Figure 2 the conductor 15' is broken to afford terminals 35 and 36, which are connected in circuit with the center tap 28 of the thermocouple 22 by means of lead conductors 29a and 2%, said lead conductors being thereby connected in series circuit relation. The conductors 29a and 29b are preferably substantially coextensive with the lead conductors 26' and 27 and may be embodied therewith into a single cable. The opera- -3- tion of the form of the invention shown in Figure 2 is substantially the same as that of the form of the invention shown in Figure 1 insofar as its response to the unsafe temperature of the medium sensed by the couple 22' and its response to a break in either of the parallel paths is concerned.

An additional safeguard is provided in the form of the invention shown in Figure 2, however, in that on occurrence of a break in either or both of the lead conductors 2% and 29b alternating current flow between the source 6 and the control circuit is automatically prevented by said break. This safety feature is particularly advantageous, for example in the event of complete severance of a cable comprising the leads 26, 27, 29a and 2%, since a simultaneous break in both of the leads 26' and 27 prevents both thermoelectric and alternating current flow through the coil portions 9a and 9b, and hence the armature 10' cannot be actuated to attracted position. An unsafe condition does not result, however, since further current flow between the source 6 and the control circuit is prevented by the break in the lead conductors 2% and 29b occasioned by such a cable severance.

Iaving thus described two embodiments of the present invention, it is to be understood that the illustrated forms were selected to facilitate the disclosure of the invention, rather than to lunit the number of forms which it may assume. Various modifications, adaptations and alterations may be applied to the specific forms shown to meet the requirements of practice without in any manner departing from the spirit or scope of the present invention, and all of such modifications, adaptations and alterations are contemplated as may come within the scope of the appended claims.

What is claimed as the invention is:

1. A control device comprising in combination an electromagnetic operator having at least one flux generating coil split to afiord two coil portions, a first electric source for said coil, a control member operatively related to said operator for movement from a first toward a second position in response to energization of said coil by said first source affording generation of a predetermined magnitude of actuating fiux in said coil, and a second source of electric current for energizing said coil portions in opposition, the opposing fluxes thus generated having no substantial actuating effect on said control member, occurrence of a break in either of said coil portions terminating the generation of flux therein and the opposition of said flux to that generated in the other coil portion, whereupon said last-mentioned flux effects movement of said control member from its first toward its second position.

2. A control device comprising in combination an electromagnetic operator having at least one flux generating coil split to afford two coil portions, a control member operatively related to said operator for movement from a first toward a second position in response to generation of a predetermined magnitude of actuating flux in said coil, a first source of electric curent for energizing said coil portions in opposition, the opposing fluxes thus generated having no substantial actuating eflect on said con trol member, and second current source means in circuit with said coil effective, when operative, to produce flow through said coil from one end thereof to the other of a second current sufficient to generate said predetermined magnitude of actuating flux in said coil for actuation of said control member from its first toward its second position.

3. A control device comprising in combination an electromagnetic operator having at least one flux generating coil split to afford two coil portions, a control member operatively related to said operator for movement from a first toward a second position in response to generation of a predetermined magnitude of actuating flux in said coil, a control circuit including circuit-controlling contacts for controlling the energization thereof, said contacts being operatively related to said control member for movement therewith from one controlling position to another, a first source of electric current for energizing said control circuit and for energizing said coil portions in opposition, the opposing fluxes thus generated having no substantial actuating eifect on said control member and contacts, and second current source means in circuit with said coil effective, when operative, to produce flow through said coil from one end thereof to the other of a second current sufiicient to generate said predetermined magnitude of actuating flux in said coil for actuation of said control member from its first toward its second position, occurrence of a break in either of said coil portions terminating the generation of flux therein and the opposition of said flux to that generated in the other coil portion by current from said first source, whereupon said last-mentioned flux effects movement of said control member from its first toward its second position and thereby controlling movement of said contacts.

4. A control device comprising in combination an electromagnetic operator having at least one flux generating coil split to aiford two coil portions, a control member operatively related to said operator for movement from a first toward a second position in response to generation of a predetermined magnitude of actuating flux in said coil, a first source of electric current for energizing said coil portions in opposition, the opposing fluxes thus generated having no substantial actuating effect on said control member, and condition responsive second curent source means in said circuit operable in response to a predetermined condition to produce flow through said coil from one end thereof to the other of a second curent suficient to generate said predetermined magnitude of actuating flux in said coil for actuation of said control member from its first toward its second position.

5. A control device comprising in combination an electromagnetic operator having at least one flux generating coil split to afford two coil portions, a control member operatively related to said operator for movement from a first toward a second position in response to generation of a predetermined magnitude of actuating flux in said coil, a source of alternating current for energizing said coil portions in opposition, the opposing fluxes thus generated having no substantial actuating efiect on said control member, and direct current source means in said circuit effective, when operative, to produce flow through said coil from one end thereof to the other of a direct current sufiicient to generate said predetermined magnitude of actuating flux in said coil for actuation of said control member from its first toward its second position.

6. A control device comprising in combination an electromagnetic operator having at least one flux generating coil split to afford two coil portions, a control member operatively related to said operator for movement from a first toward a second position in response to generation of a predetermined magnitude of actuating flux in said coil, a first source of electric current for energizing said coil portions in opposition, the opposing fluxes thus generated having no substantial actuating effect on said control member, and a thermoelectric generator in said circuit having at least two thermojunctions and operable in response to a predetermined temperature differential between said thermojunctions to produce flow through said coil from one end thereof to the other of thermoelectric current sufiicient to generate said predetermined magnitude of actuating flux in said coil for actuation of said control member from its first toward its second position.

7. A control device comprising in combination, an electromagnetic operator having at least one flux generating coil having a pair of terminals and a center tap, a control member operatively related to said operator for movement from a first to a second position in response to generation of a predetermined magnitude of actuating flux in said coil, first current source means having a pair of terminals and a center tap, first and second leads connecting the terminals of said first source respectively to the terminals of said coil, said first source means, when operative, being effective to produce flow through said coil from one of its terminals to the other of a first current sufficient to generate said predetermined magnitude of actuating flux in said coil for actuation of said control member from its first toward its second position, and a second source of current having one terminal connected in circuit with the center tap of said first current source means and having another terminal connected in circuit with the center tap of said coil to provide parallel paths comprising the respective halves of said coil and first source and the respective leads connecting said halves to said second source for the flow of a second current and generation of said predetermined magnitude of fiux in one half of said coil which opposes a similar magnitude of flux generated in the other half of said coil, said opposing fluxes having no substantial actuating effect on said control member, occurrence of a break in either of said parallel paths terminating the generation by said second current of said flux in the half of said coil in the broken path and the opposition of said flux to the flux generated by said second current in the half of the coil in said other parallel path, whereupon said last-mentioned flux effects movement of said control member from its first toward its second position.

8. A control device comprising in combination, an electromagnetic operator having at least one flux generating coil having a pair of terminals and a center tap, a control member operatively related to said operator for movement from a first to a second position in response to generation of a predetermined magnitude of actuating flux in said coil, a thermoelectric generator having a pair of terminals and a center tap, first and second leads connecting the terminals of said first source respectively to the terminals of said coil, said generator, when operative, being effective to produce flow through said coil from one of its terminals to the other of thermoelectric current sufiicient to generate said predetermined magnitude of actuating flux in said coil for actuation of said control member from its first toward its second position, and a source of alternating current having one terminal connected in circuit with the center tap of said generator and having another terminal connected in circuit with the center tap of said coil to provide parallel paths comprising the respective halves of said coil and generator and the respective leads connecting said halves to said source for the flow of alternating current and generation of said predetermined magnitude of alternating current flux in one half of said coil which opposes a similar magnitude of alternating current flux generated in the other half of said coil, said opposing fluxes having no substantial actuating efiect on said control member, occurrence of a break in either of said parallel paths terminating the generation of alternating current flux in the half of said coil in the broken path and the opposition of said flux to the alternating current flux generated in the half of the coil in said other parallel path, whereupon said last-mentioned flux etfects movement of said control member from its first toward its second position.

9. A control device comprising in combination, an electromagnetic operator having at least one flux generating coil having a pair of terminals and a center tap, a control member operatively related to said operator for movement from a first to a second position in response to generation of a predetermined magnitude of actuating flux in said coil, first current source means having a pair of terminals and a center tap, first and second leads connecting the terminals of said first source respectively to the terminals of said coil, said first source means, when operative, being effective to produce flow through said coil from one of its terminals to the other of a first current sufiicient to generate said predetermined magnitude of actuating flux in said coil for actuation of said control member from its first toward its second position, and a second source of current having one terminal connected in circuit with the center tap of said first current source means through a third lead and having another terminal connected in circuit with the center tap of said coil to provide parallel paths comprising the respective halves of said coil and first source and the respective leads connecting said halves to said second source for the fiow of a second current and generation of said predetermined magnitude of flux in one half of said .coil which opposes a similar magnitude of flux generated in the other half of said coil, said opposing fiuxes having no substantial actuating effect on said control member, occurrence of a break in either of said parallel paths terminating the generation by said second current of said flux in the half of said coil in the broken path and the opposition of said flux to the flux generated by said second current in the half of the coil in said other parallel path, whereupon said last-mentioned flux effects movement of said control member from its first toward its second position, a control circuit under the control of said control member having a first terminal connected in circuit with said one terminal of said second source through a fourth lead connected to said third lead at the center tap of said first source and having a second terminal connected in circuit with said other terminal of said second source, Wherefore on occurrence of a break in either of said third and fourth leads current fiow from said second source to said control circuit is prevented.

10. A control device comprising in combination, an electromagnetic operator having at least one flux generating coil having a pair of terminals and a center tap, a control member operatively related to said operator for movement from a first to a second position in response to generation of a predetermined magnitude of actuating flux in said coil, a thermoelectric generator having a pair of terminals and a center tap, first and second leads connecting the terminals of said first source respectively to the terminals of said coil, generator, when operative, being efiective to produce fiow through said coil from one of its terminals to the other of a thermoelectric current sufficient to generate said predetermined magnitude of actuating flux in said coil for actuation of said control member from its first toward its second position, and a source of alternating current having one terminal connected in circuit with the center tap of said generator through a third lead and having another terminal connected in circuit with the center tap of said coil to provide parallel paths comprising the respective halves of said coil and generator and the respective leads connecting said halves to said source for the flow of alternating current and generation of said predetermined magnitude of alternating current flux in one half of said coil which opposes a similar magnitude of alternating current fiux generated in the other half of said coil, said opposing fluxes having no substantial actuating effect on said control member, occurrence of a break in either of said parallel paths terminating the generation of alternating current fiux in the half of said coil in the broken path and the opposition of said flux to the alternating current flux generated in the half of the coil in said other parallel path, whereupon said last-mentioned flux efiects movement of said control member from its first toward its second position, a control circuit under the control of said control member having a first terminal connected in circuit with said one terminal of said alternating current source through a fourth lead connected to said third lead at the center tap of said generator and having a second terminal connected in circuit With said other terminal of said source, wherefore on occurrence of a break in either of said third and fourth leads alternating current flow from said source to said control circuit is prevented.

11. A control device comprising in combination, an electromagnetic operator having at least one flux generating coil having a pair of terminals and a center tap, a control member operatively related to said operator for movement from a first to a second position in response to generation of a predetermined magnitude of actuating flux in said coil, a thermoelectric generator having a pair of terminals and a center tap, first and second leads connecting the terminals of said first source respectively to the terminals of said coil, generator when operative, being effective to produce flow through said coil from one of its terminals to the other of thermoelectric current sufi'lcient to generate said predetermined magnitude of actuating flux in said coil for actuation of said control member from its first toward its second position, and a source of alternating current having one terminal connected in circuit with the center tap of said generator through a third lead and having another terminal connected in circuit with the center tap of said coil to provide parallel paths comprising the respective halves of said coil and generator and the respective leads connecting said halves to said source for the flow of alternating current and generation of said predetermined magnitude of alternating current flux in one half of said coil which opposes a similar magnitude of alternating current flux generated in the other half of said coil, said opposing fiuxes having no substantial actuating efiect on said control member, occurrence of a break in either of said parallel paths terminating the generation of alternating current flux in the half of said coil in the broken path and the opposition of said fiux to the alternating current flux generated in the half of the coil in said other parallel path, whereupon said last-mentioned flux efiects movement of said control member from its first toward its second position, a control circuit having a first terminal connected in circuit with said one terminal of said alternating current source through a fourth lead connected to said third lead at the center tap of said generator and having a second terminal connected in circuit with said ther' terminal of said source, Wherefore on occurrence of a break in either of said third and fourth leads alternating current flow from said source to said control circuit is prevented, said control circuit including circuit controlling contacts operatively related to said control member for movement from a circuit-making position to a circuit-interrupting position preventing alternating current flow through said control circuit on movement of said control member from said first to said second position. 12, In combination, a control circuit energized from a first source, an electroresponsive control device for controlling said circuit, a thermoelectric generator for energizing said control device, said generator being provided with first and second leads connecting it in circuit with said control device, and said control circuit including third and fourth leads substantially coextensive with said first and second leads and joined adjacent said generator in series circuit relation, Wherefore a break in either of said third and fourth leads interrupts the flow of current from said first source to said control circuit.

13. A control device comprising in combination, an electromagnetic operator having coil means having terminals and a tap, a control member operatively related to said operator for movement from a first to a second position in response to generation of a predetermined magnitude of actuating flux in said coil means, first current source means having terminals and a tap, first and second leads connecting the terminals of said first source respectively to the terminals of said coil means, said first source means when operative, beingeflective to produce flow through said coil means from one of its terminals to another of a first current suificient to generate said predetermined magnitude of actuating flux of said coil for actuation of said control member from its first to- Ward its second position, and a second source of current 9 having one terminal connected in circuit with the tap of said first current source means and having another terminal connected in circuit with the tap of said coil means to provide separate paths comprising the respective portions of said coil means and first source and the respective leads connecting said portions to said second source for the flow of a second current and generation of said predetermined magnitude of flux in one portion of said coil means which opposes a similar magnitude of flux generated in the other portion of said coil means, said opposing fluxes having no substantial actuating effeet on said control member, occurrence of a break in either of said separate paths terminating the generation 10 by said second current of said flux in the portion of said coil means in the broken path in the opposition of said flux to the flux generated by said second current in the portion of the coil in said other separate path, whereupon said last-mentioned flux effects movement of said control member from its first toward its second position.

References Cited in the file of this patent UNITED STATES PATENTS 2,428,568 Hill Oct. 7, 1947 2,456,541 Stoecklin 'Dec. 14, 1948 2,505,730 Betz Apr. 25, 1950 2,691,707 Lovejoy Oct. 12, 1954 

